1. Field of the Invention
The present invention relates generally to devices and methods for analyzing an electromagnetic signal and, more particularly, to devices and methods of analyzing an electromagnetic signal power spectrum.
2. Related Art
Spectrum analyzers for use in analyzing signals at radio frequencies are available. For example, U.S. Pat. No. 6,392,397 to Thomas describes a spectrum analyzer that includes a frequency converter for converting, at each of a series of frequency settings, a received radio frequency signal into an intermediate frequency signal, each intermediate frequency signal being derivable from more than one nominal received radio frequency signals. The converter includes a frequency synthesizer for synthesizing the frequencies of the frequency settings and a mixer for mixing each synthesized frequency with the received radio frequency signal in a complex manner such that the candidate frequency intervals corresponding to an arbitrary frequency interval Fif are given by N.Fref±Fif, where N is any positive integer and Fref is the synthesized frequency.
In operation, the spectrum analyzer carries out a frequency analysis of each intermediate frequency signal to produce a power spectrum thereof and constructs a composite received radio frequency signal power spectrum corresponding to each intermediate frequency signal power spectrum. The composite radio frequency signal power spectrums are then operated on by the spectrum analyzer to provide the actual power spectrum of the received radio frequency signal.
Such a power spectrum analyzer suffers from the drawback of high cost and complexity resulting from extensive circuitry including filters, dividers, clocks, etc.